Gripper shuttle



' Oct. 14, 1969 A. SCHNEIDER GRIPPER SHUTTLE Filed March 5, 1968 12 17 114 Inventor:

Arthur Schneider ATTORNEYS United States Patent 3,472,286 GRIPPERSHUTTLE Arthur Schneider, Winterthur, Switzerland, assignor to SulzerBrothers Limited, Winterthur, Switzerland, a Swiss company i Filed Mar.5, 1968, Ser. No. 710,505

Claims priority, application Switzerland, Mar. 7, 1967,

3,382/67 Int. Cl. D03d 47/24, 47/00 US. Cl. 139-125 7 Claims ABSTRACT OFTHE DISCLOSURE The present invention relates to a gripper shuttle forpicking the wefts in looms having a weft supply bobbin remaining outsidethe shed, the shuttle comprising a resilient weft gripper surrounded bya substantially rigid but hollow shuttle body or casing.

The weft gripper is a device comprising two resilient arms which areconnected by a yoke and whose free ends carry two jaws and urge thesejaws together with a certain prestressing.

The shuttle body is generally in the form of a flat, hollow casingsurrounding the gripper and screening or shielding it off from theexterior. The yoke of the gripper is attached to the head of the shuttlebody inside the shuttle or it may itself form this head. During pickingthe head points towards the catching side of the loom, The jaws are atthe end of the casing, where it is usually open, and where the jaws areprotected from damage from the exterior and where there is enough spaceinside the casing for the gripper to open and close.

In the picking motion of the loom, the jaws of the weft gripper areseparated, for example by inserting a plunger opener between the tworesilient arms, through suitable openings in the side walls of theshuttle body. The resilient arms, with the two jaws which are attachedto to their ends, are thus parted so that they can receive the end ofthe weft.

A yarn feed having a similarly constructed but movable gripperintroduces the weft end between the open jaws of the shuttle gripper, ata recess in the rear end of the shuttle. body. As soon as the plungeropener is withdrawn, the jaws close on the weft and grip it. The yarnfeed then releases the weft, and the shuttle is shot through the openshed by the picking motion, while the gripper pulls the weft after itand thereby picks it through the shed.

To prevent any deviation of the shuttle from its path and any directcontact with the warp threads during picking, the shuttle is guided inthe shed by a series of teeth on the sley which are arranged like acomb. These teeth are for example cut and machined from sheet steel.During picking, i.e. when the shed is open and the reed has swung backinto its position of rest, these teeth project through the warp threadsinto the shed, During the throw of he reed and the change of shed, theyare pivoted out of the shed. On the catching side the shuttle is caughtand braked by the catching motion.

When released, the shuttle is ejected onto a conveying device andreturns outside the shed to the picking station, to repeat the cycle.Meanwhile other shuttles the exact number depends on the picking rate,on the weft pattern, and the width of the loom and may be up to 18shuttles 3,472,286 Patented Oct. 14, 1969 per loom in the case of knownlooms--have been put through the same cycle an have picked furtherwefts.

To reduce the metal abrasion which occurs as the shuttle runs throughthe track formed by the guide teeth and as the gripper opener enters,the shuttles are usually slightly lubricated by an oil mist before theyreach the picking point. With known designs residual oil, dust and fluffinvariably collect during operation inside the shuttle body, and whenthe shuttle has been in use for a fairly long period the cavities fillwith compact material which interferes with satisfactory operation ofthe weft gripper, ultimately making picking of the weft uncertain. Sincethe shuttles used in the loom must therefore be changed and cleanedperiodically, each loom requires two sets of shuttles. Cleaning may forexample consist in placing the used shuttles in a petroleum bath inorder to soften the solidfied residues, whereupon the deposits can beremoved with mechanical means such as hooks, scrapers and compressedarr.

The resilient arms of the gripper are subjected to mechanical stressesas the gripper is repeatedly operated by the opener, and as the shuttleleaves the picking motion and runs through the track formed by the guideteeth. Apart from the direct effects of spring tension and inertia, somevibrations is imposed, especitally on the resilient elements of theshuttle, by intermittent external influences. This vibration may lead tofatigue fractures of the spring gripper arms. To prevent arms fracturedfor this reason from causing the loom to break down, it has already beenproposed that a rubber insert should be stuck to the portion of the armswhich is subjected to most stress, i.e. to their foot, immediatelybeside the yoke between the two arms. This insert holds a broken arminside the shuttle body. With this known design of gripper shuttlehowever the space between the spring arms and the inside wall of theshuttle body must be left vacant to give the resilient arms sufficientroom to move when the gripper is operated by the opener, and thesecavities in the shuttle body must be cleaned periodically.

It is an object of the invention to prevent dust and oil residues fromentering the shuttle body and to reduce vibration in the spring arms ofthe weft gripper.

According to the invention, the space between the spring arms of thegripper and the inside wall of the shuttle body is at least partlyfilled with resilient inserts which seal this space off from theexterior.

In another embodiment of the invention, the space between the two springarms of the gripper is at least partly filled by a further resilientinsert which seals that space relative to openings in the shuttle body.The inserts must not interfere with motion and operation of the springarms, and the sealing effect of the inserts should extend over the wholerange of deflection of the :arms. To this end, the inserts are formed,at least in part, of a resilient foam material, preferably asilicone-based plastic.

For greater resilience the inserts sealing the cavities in the shuttlebody may contain recesses, or voids, or they may fill the cavitiesincompletely, but they must be such as to provide a dustproof closurefor the openings as far as possible.

If there is intimate contact between the spring arms and the insertswhich seal oif the interior of the shuttle body, the vibration to whichthe arms are exposed can be substantially eliminated by choice ofsuitable materials. This is the case especially if the inserts arefastened, preferably by adhesive, to the spring arms and optionally tothe inside wall of the shuttle body along the narrow edge thereof.Experiments have shown that if vibrations of the spring arms areprevented, the spring tension or prestressing acting on the jaws holdingthe weft can be reduced by up to 25% without afiecting reliability ofthe gripper. Because effective damping of the vibrations pere) mits asubstantial reduction in the initial spring tension, there can be asubstantial reduction in the long-term stresses arising from thistension and in the wear on the opener and on the resilient arms of thegripper, and the weft can be handled more gently.

Preferably, therefore, instead of all inserts being made of resilientfoam material, at least one insert is made of a homogeneous, i.e.compact and tougher material. For example, a silicone rubber has proveda very efficient vibration-damping material on account of its resistanceto aging, its insensitivity to chemical influences and to temperaturechanges, and its toughness.

The construction and mode of operation of the gripper shuttle embodyingthe invention will now be described in further detail with reference toembodiments shown in the accompanying drawings.

Brief description of the drawings In the drawings:

FIG. 1 shows a longitudinal section through a shuttle embodying theinvention, taken on the line I-I in FIG. 2;

FIG. 2 is a plan sectional view of the shuttle shown in FIG. 1, takenalong the line IIII of FIG. 1;

FIG. 3 is a cross-section through the same shuttle along the line IIIIIIin FIG. 2, illustrating operation of the plunger opener; and

FIG. 4 is a fragmentary sectional view, similar to that of FIG. 2,through the end portion of another embodiment of the invention in whichan insert contains recesses.

Description of the preferred embodiment Referring to FIGS. 1 and 2, thegripper shuttle there shown has two spring arms 1 and a yoke 2 attachedby rivets 3 to the head 4 of the tubular shuttle body 5. The gripperjaws 6, carried by the arms 1, are inside the rear end 7 of the shuttlebody 5. During weaving the yarn feed (not shown) inserts the weft end 8,which is to be picked through the shed of the loom, between the two jaws6 in a recess 9 in the shuttle body 5, the jaws 6 being open. The jawsare opened by inserting a plunger opener 10 a conical or wedge-shapedpinthrough openings 11 in the shuttle body and between the arms 1 asindicated in FIG. 3. The arms and therefore the jaws 6 which are carriedand pressed together by them are therefore splayed, in spite of thespring tension. To close the gripper, the opener is withdrawn, whereuponthe jaws grip the weft end 8. During picking the shuttle pulls the weftafter it, carrying it between the open warp threads as it passes throughthe shed.

To prevent oil mist and dust from entering and settling in the cavity atthe rear end '7 between the arms 1 and the inside wall of the shuttlebody, that cavity is filled with soft, resilient inserts 12 which arecemented or otherwise fastened to the arms 1 and to the inside wall ofthe narrow side of the shuttle body. These inserts are made of aresilient but dustproof material, preferably a siliconebased foammaterial, which can be inserted by injection moulding into the alreadyassembled shuttle and which adheres firmly to the metal components.Alternatively, the inserts may be made up in suitable shapes and thenincorporated into the shuttle. The resilience of the inserts 12 may beincreased by providing voids or recesses 13 inside them (in the form oflarge pores in the foam) or on the outside of them, as shown in theembodiment of FIG. 4.

Foreign matter can enter the shuttles previously proposed not only atthe open rear end thereof but also through the hole provided to receivethe jaw-separating pin, and may adhere between the gripper armsthemselves. In addition to the inserts 12, therefore, a further insert14 may be added to the shuttle of the invention, filling at least partof the space between the two arms 1 and sealing it off from the opening11, This insert 14 is afiixed to the two arms by adhesive. Apart fromits sealing effect, it serves to damp the vibrations caused in the armsby shocks from outside, and also, in the event of an arm fracturing, tohold the broken portion inside the shuttle body and so to preventbreakdown of the loom.

While the invention has been hereinabove described in terms of a numberof presently preferred embodiments, the invention itself is not limitedthereto. For example, other materials may be used for the variouscomponents. Thus the shuttle body 5 may be made of steel, of anothermetal, or of a thermoplastic or thermo-setting plastic. The inserts 12which at least in part fill the space or clearance between the arms 1and the inside of the body 5, and the insert 14 which at least in partfills the space between the arms 1, may be made of different materialsand/or inserted or attached in different ways, to adapt them better todifferent stresses and requirements. More generally, the inventioncomprehends all modifications on and departures from the embodimentshereinabove described properly falling within the spirit and scope ofthe appended claims.

I claim:

1. A gripper shuttle comprising a weft gripper having spaced arms, ahousing surrounding the gripper with clear- :ance therefrom, and insertsof resilient material at least partly filling said clearance.

2. A gripper shuttle according to claim 1 wherein said inserts at leastpartly fill the space between the arms of said gripper.

3. A gripper shuttle according to claim 1 wherein said materialcomprises a foam.

4. A gripper shuttle according to claim 3 wherein said foam is asilicone-based plastic.

5. A gripper shuttle according to claim 1 wherein at least one of saidinserts encloses voids.

6. A gripper shuttle according to claim 1 wherein at least one of saidinserts is free from pores.

7. A gripper shuttle according to claim 1 wherein at least one of saidinserts is made of a vibration-damping material.

References Cited UNITED STATES PATENTS 2,599,731 6/1952 Whewell 1391252,660,201 11/1953 Darash 139-425 2,759,496 8/1956 Pf-arrwaller 1391253,048,197 8/1962 Fink 139207 3,140,731 7/1964- Jones 139-126 3,237,7653/1966 Klein et a1. 139125 3,348,582 10/1967 Brookshire l39122 X JAMESK. CHI, Primary Examiner

